Using Renyi's information and wavelets for target detection: An application to mammograms

In this paper we represent a multi-scale method for the detection of small targets embedded in noisy background. The multi-scale representation is bui lt using a weighted undecimated discrete wavelet transform. The method, in essence, is based on the maximisation of information available at each reso lution level of the representation. We show that such objective can be achi eved by maximising Renyi's information. This approach allows us to determin e an adaptive threshold useful for discriminating, at each scale, between w avelet coefficients representing targets and those representing background noise. Eventually, avoiding inverse transformation, scale-dependent estimat es are combined according to a majority vote strategy. The proposed techniq ue is experimented on a standard data set of mammographic images.